In cable systems, it is desirable to provide for automatic or self-adjustment to take up slack in the systems, For example, in a parking brake system, three cables might be used, each of which includes a conduit and a strand extending through the conduit. The cables are interconnected such that a force applied to a first cable is transmitted to the second and third cables extending to the rear brakes.
In application Ser. No. 832,526 filed Feb. 21, 1986, having a common assignee with the present application, there is disclosed a self-adjusting cable control device for automatically compensating for wear in a control cable system. The device includes a termination member connected at one end of a control cable and a connecting member attached to an actuation member. The connecting member carries a clutch for locking with the termination member upon application of force to the actuation member. Spring means are provided to move the cable with respect to the actuation member when the clutch is disengaged from the termination member. The clutch comprises a plurality of collet members which are movable radially and longitudinally and surround the termination member. The collet members have conical surfaces at one end adapted to engage complementary conical surfaces on the connecting member and serrations which engage complementary serrations on the collet members. The control device further includes a release tube that is accessible from the exterior of the device and can be engaged and moved axially inwardly by a clip to disengage the collet members and thereby permit easy connection of the device to the cables. In addition, provision is made for a separate clip normally holding the tube in a position and operable to release the release tube and the collet members to operative position.
Among the objectives of the present invention are to provide a self-adjusting system which functions on the basis of changing the anchorage point on a conduit to maintain the conduit system; which is low in cost, lighter in weight, wherein the weight is supported by a conduit rather than a strand, wherein the strand loads are in line, and which can be readily assembled for use.
In accordance with the invention, the self-adjusting cable system comprising first, second and third cables, each including a conduit and a strand extending through the conduit. A self adjusting mechanism is provided and includes a collet housing, an inner member movable axially relative to the collet housing and a clutch between the housing and the member comprising a plurality of collet members which are movable radially and longitudinally and surround the member to cause teeth on the collets to disengage and engge teeth on the axially movable member. A spring extends between the collet housing and the conduit of the first cable. The strand of the first cable is connected to the movable member of the collet assembly. The strand of the first cable extends through the inner member of the collet clutch and is attached to the strand of the third cable. The strand of the second cable is connected to the collet housing. When a load is applied to the strand of the first cable, the strand tends to move toward the collet housing. The resisting force created by the second and third cables causes the collets to be forced into locking position to sustain the load. If there is slack in the system, the spring exerts force between the collet housing and the first conduit until a balance of force occurs, the collets moving out of engagement with the movable member until the slack is removed.